1. Technical Field
The present disclosure relates to a drivetrain module for a motor vehicle. In particular, a drivetrain module having a flywheel and having a crankshaft starter-generator, and a corresponding motor vehicle, are described.
2. Description of Related Art
To permit the initial mixture formation, ignition and combustion in an internal combustion engine, internal combustion engines are brought to a minimum rotational speed by way of the external mechanical drive of a starter. For this purpose, drivetrain modules are known from the prior art in which electrically operated crankshaft starter-generators are arranged between internal combustion engine and gearbox. Aside from the starter function, the crankshaft starter-generator can, during a braking process, recuperate energy by virtue of the crankshaft, decoupled from the internal combustion engine, driving the crankshaft starter-generator. By virtue of the recuperated energy being converted in the crankshaft starter-generator in order to assist the internal combustion engine during starting and acceleration, fuel consumption can be reduced. Furthermore, the crankshaft starter-generator may serve as a generator replacement during driving operation.
FIG. 1A shows, in the upper half of the figure, a section, and in the lower half of the figure, a view, of a conventional drivetrain module 10 for a motor vehicle. The image plane is parallel to an axis of rotation 1 of a crankshaft. A drivetrain module 10 of this type is known from the laid-open specification DE 10 2013 018 720 A1. The conventional drivetrain module 10 comprises a flywheel 2, which is connected to the crankshaft, and a rotor 4, which bears in frictionally locking fashion against a web 3 integrally formed on the flywheel 2. A shell surface of the web 3 forms a press-fit seat 5 onto which a radially internally situated fit surface 6 of the rotor 4 is pressed, as shown in the perspective illustration of FIG. 1B. Therefore, an axial length of the web 3 must correspond at least to the axial length of the rotor 4. The exploded drawing of FIG. 1C shows the flywheel 3 and rotor 4 with exposed press-fit seat 5 and fit surface 6. The flywheel 2 comprises a starter toothed ring 8.
The mass moment of inertia is thereby increased. The fuel saving is adversely influenced by the increased mass moment of inertia.
A disadvantage of this is that the flywheel must have an additional attachment surface which is at least the length of the rotor.